1. Field of the Invention
The present invention relates to a process for producing a chocolate having improved stability which is free from blooming even when exposed to high temperatures or stored for a long period of time under severe temperature changes.
2. Discussion of the Background
When chocolate is exposed to high temperatures in summer or stored under such conditions that the temperature varies greatly, a white powder spreads on the surface. This phenomenon is called blooming and notably decreases the commercial value of the chocolate.
Generally, chocolate is prepared by mixing a cacao mass, fats and oils such as cacao butter or the like, cocoa, saccharides, milk powder and the like as required, and subsequently subjecting the mixture to rolling, conching and tempering. Blooming can include either or both of (a) a fat bloom, based on unstable crystals of fats and oils of the starting material, and (b) a sugar bloom, caused by recrystallization of sugar. The former fat bloom is especially common and observed in many cases.
In order to prevent the occurrence of a fat bloom, there have been a variety of previous proposals as noted below.
(1) One method involves incorporation of stable crystalline particles of 2-unsaturated-1,3-di-saturated glyceride composed of an unsaturated fatty acid having 18 or more carbon atoms and a saturated fatty acid having from 20 to 24 carbon atoms in chocolate, with the intent being to keep the original palatability of the chocolate even after it is exposed to a high temperature (close to body temperature) for a fixed period of time (Japanese Patent Publication No. 83,680/1995).
(2) A further method involves use of a sucrose fatty acid ester having a HLB value of 19 or more as an emulsifying agent in the production of chocolate (Japanese Patent Publication No. 108,183/1995).
(3) Another method involves providing a chocolate that incorporates (a) a fatty acid component in a lauric acid-type hard butter and a sucrose fatty acid ester that is myristic acid, and (b) a sucrose fatty acid ester having an average substitution ratio of fatty acid to sucrose of between 5 and 7 (Japanese Patent Publication No. 40,880/1995).
(4) An additional method involves using fats and oils composed mainly of triglyceride in which total carbon atoms of 1,3-saturated-2-unsaturated fatty acid residue are between 50 and 56 (Japanese Patent Publication No. 95,879/1994).
(5) A further method involves formation of a fine crystalline core during solidification when producing chocolate, in order to release the solidified product from a mold, or to retain excellent properties of gloss, palatability, mouth feeling and the like [Japanese Laid-Open Patent Application (Kokai) No. 40,750/1986).
As noted above, the chief improvement that has been made so far relates mainly to the fat component, including cacao butter, a main component of chocolate. However, resistance to high temperature exposure has not been satisfactory yet, and consequently a person sometimes obtains a chocolate having a fat bloom. Further, some fatty acids taste bitter and feel rough. Add to this a further disadvantage that cacao, cacao butter and the like, which are the main starting materials in chocolate production, are natural products and therefore have a wide range of qualities. This greatly influences the qualities of the final product. Thus, treatment of the fat bloom must also take into consideration the qualities of the natural starting materials.